XnView 2.12 Multilingual

Free graphic and photo viewer without installation.
Download Portable XnView Full Online (0.3 MB)
Download Portable XnView Standard Online (0.3 MB)

Extract and run XnViewPortable.
Copy Adobe Photoshop Plugins (*.8bf) in Data\8bf

Edit XnViewPortable.ini to fix Cache:
Cache=Disabled Default
Cache=Temp Cache set in Windows Temp folder deleted when leaving
Cache=Portable Cache set in Data\Cache

If you drag'n drop a file on (or open with) XnViewPortable: it will be opened in XnView.
Settings of installed XnView should be preserved.

Portable GIMP 32-64 bit Multilingual

GNU Image Manipulation Program without installation.
Download Portable GIMP 32-64 bit Multilingual (62 MB)
Extract and run GIMPPortable.
Copy additional fonts in Data\GIMP\fonts
To change language, add GIMPLanguage=(one of the subfolders names in \App\GIMP\share\locale) in GIMPPortable.ini
If you drag'n drop a file on (or open with) GIMPPortable: it will be opened in GIMP.
Settings of installed GIMP should be preserved.